Introduction Chile is a middle-income country that has experienced progressive economic stability and improvement of its health status, however, one persistent and complex public health problem is disability. Social determinants of health have emerged as a significant aspect of current debates on this health problem. This analysis focuses on the international immigrants, who have not necessarily benefited from the country's economic development.

Objective To compare the social determinants of disability between the international immigrants and the Chilean-born population.

Methods Cross-sectional analysis of a Chilean population-based survey of 268 873 people. Independent variable: any disability (visual/hearing/speaking/learning/physical/psychiatric; dichotomous variable). Dependent variables: socio-demographics (age/sex/marital status/geographic location), socio-economics status (3 categories, low/medium/high, by combining income, occupation and education through complete-linkage hierarchical cluster analysis), and material living standards (overcrowding/sanitary conditions/quality of the housing). Descriptive, comparative and adjusted multiple logistic regression models were estimated using STATA 10.0.

Results 1% of the sample reported being an international immigrant and a further 0.67% did not respond to the question on migration status. International immigrants reported a lower prevalence of disability than the Chilean-born (3.55% vs 6.93%, p<0.001); and a clear inverse gradient of disability emerged by immigrants' socio-economic status. There was a significant association with single status, self-employed/public-sector employees, and being ill and retired (p<0.001). International immigrants living >20 years in Chile and those from Peru had a higher chance of disability (OR 2.95 and 7.85, respectively). A protective effect of living in rural areas (OR 0.99) and a negative association with adequate quality of material living standards (OR 0.96) was also found. Those who preferred not to report their migration status showed a higher prevalence of disability than the international immigrants (7.42%, p<0.001), particularly if they were in the poorest income quintile (OR 6.91).

Discussion Social determinants of disability varied between the international immigrants, those who did not respond to the migration status question and the Chilean-born population. Immigrants showed a clear inverse gradient of disability by socio-economic status. A possible healthy migrant effect was apparent among the international immigrants, but disappeared after 20 years living in Chile. Those who did not respond to the question on migration, potentially undocumented immigrants, showed some particular poverty-related vulnerability towards disability. Overall, international immigrants were a complex and heterogeneous group and their social determinants for disability require further consideration in future health policy interventions in Chile.